Inspection tool for solderless wire connections



Aug. 21, 1956 J. R. 508 ETAL 2,759,357

INSPECTION TOOL FOR SOLDERLESS WIRE CONNECTIONS Filed June 4, 1954 BOBEET B. SHULTEBs /3,, (M-n, yw, flwfl/ofi EZ'F E United States Patent INSPECTION TOOL FOR SOLDERLESS WIRE CONNECTIONS John R. Bos, Grand Haven, and Robert B. Shulters, Spring Lake, Mich., assignors, by mesne assignments, to Gardner-Denver Company, a corporation of Delaware Application June 4, 1954, Serial No. 434,624

Claims. (Cl. 73-141) The present invention relates generally to the connection of wires to terminals and more particularly to a tool for inspecting solderless connections between wires and terminals.

Recently there have been developed tools by means of which a wire is helically wound about a terminal in contiguous convolutions under controlled tension so that electrical connection is effected therebetween without necessity for subsequent application of solder to insure the formation of a good connection. In use such tools are subject to wear so that their effectiveness becomes impaired. As a result a wire wound thereby might either be so loosely wound as to prevent a good connection or it might be so tightly drawn as to be stretched beyond its elastic limit whereby failure under stress might obtain.

An object of the present invention, therefore, is to provide a tool for inspecting connections made by such devices so as to detect performance variations thereof whereby both loose and overly tight connections can be readily ascertained.

A more specific object lies in the provision of an inspection tool whereby a connection comprising a plurality of convolutions of a wire wound about a terminal can be stripped from the terminal, and the amount of force required to do so can be readily and accurately measured.

Still another object is to provide a tool of the foregoing character which is compact, effective in operation, easily manipulable, and which permits of economical manufacture.

The objects of the invention thus generally set forth together with other objects and ancillary advantages are attained by the construction and arrangement shown by way of illustration in the accompanying drawing, in which:

Figures 1 and 2 are side elevations of an inspection tool embodying the features of the present invention and respectively showing components of the device in different relative positions.

Fig. 3 is a fragmentary perspective view of the forward or nose end of the tool shown in the preceding figures.

Fig. 4 is a transverse section taken substantially in the plane of line 44 in Fig. 3.

Fig. 5 is a fragmentary section taken substantially in the plane of line 55 in Fig. 1.

While the invention is susceptible of various modifications and alternative constructions, there is shown in the drawing and will herein be described in detail a preferred embodiment, but it is to be understood that it is not thereby intended to limit the invention to the specific form disclosed, but it is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawing, there shown is an inspection tool, generally designated 10, embodying the features of the present invention. The inspection tool it) includes a pair of jaws for respectively engaging a terminal and the convolutions of wire applied thereto which jaws are relatively movable so as to apply a force axially of the terminal in a direction to strip the wire therefrom, together with means for measuring the amount of force required to effect the stripping.

As shown, the tool 10 includes a jaw 12 having a bifurcated outer end portion defining a longitudinal slot 14 for the reception of a terminal T. The jaw 12 is equipped with a thumb screw 16 for clamping the terminal T in fixed relation thereto. Thus the screw 16 is received in a complementally threaded passage 18 formed transversely in one side of the jaw 12 adjacent its outer end. The screw is adapted to extend through the passage 18 so that its outer end is in position to engage the terminal T when inserted in the slot 14 to clamp the terminal against the opposite side of the slot 14 of the jaw 12.

The tool 10 also includes a jaw 20 which, like the jaw 12, has a bifurcated outer end portion defining a slot 22 in alinement with the slot 14 of the jaw 12 for the reception of the terminal T therein. Since it is unnecessary that the jaw 20 have any clamping means thereon the jaw 20 may be made substantially thinner than the jaw 12 thereby reducing the over-all dimensions of the outer end portion of the tool 10. It will be seen from the drawings that the outer end portion of the jaw 20 is thinned and adjacent its outer end is formed so that its outer surface lies substantially transverse to the axis of the terminal T.

In order to apply a force to the convolutions of a wire W wound about the terminal T, the jaws 12 and 20 are made relatively movable. In the present instance their rear end portions are pivoted on a through-pin 24. Axial force is applied to the convolutions of the wire W, which form the connection between it and the terminal T, by separating motion of the jaws 12 and 20. Thus the jaws 12 and 24) are respectively rigid with relatively movable handles 26 and 27 which are so formed with respect to the pivot pin 24 that movement of the handles toward each other results in separating movement of the jaws.

The jaws are normally maintained in closed relation by means of an expansion type return spring 23 which is interposed between and respectively connected to the handles 26 and 27 on the opposite side of the pivot pin 24 from the jaws. In other words the spring 28 functions in a manner normally tending to bias the handles outwardly and in so doing biases the jaws toward a normally closed position.

In view of the foregoing it will be seen that the instant tool is of pliers-like form constructed and arranged to permit the application of a stripping force to the convolutions of wire, which are wound about a terminal to define an electrical connection therewith, by the application of a squeezing force to the handles 26 and 27 by a user of the tool.

Means is provided to measure the amount of force required to effect stripping of the convolutions of the wire W from the terminal T. For this purpose, in the illustrative device, one of the handles is made relatively flexible with respect to the other so that upon application of a squeezing force to the handles relative movement therebetween is effected. It will be appreciated, of course, that such relative movement will be directly proportional to the amount of force required to effect stripping of the wire from the terminal. Thus the tool is equipped with scale means for measuring the amount of the displacement of the flexible handle with respect to the rigid handle.

As shown, the handle 27 has its rear end portion formed of flexible resilient material such, for example, as a spring steel leaf 29. Spring steel leaf 29 is attached to the forward portion of the handle 27 by means of a screw 30.

In order to measure the amount of flexure of the handle portion with respect to-the handle 26 the outer end -of-the handle portion-294s adapted 'to traverse -a fined scale 32 which may be appropriately calibrated to indicate directly the stripping force, as for example in pounds. 'The scale '32 is formed 'onan-areuate finger ZM extending out-wardly from theouter-end er arigid arm 36 which is fixed at its forwardendtot'he handle 27 as by rivets or the like indicated at'37.

In order to insure uniform application "of force to *deflect the handle portion 29 upon squeezing the handles 26 and'27 toward each-other "in successive operations of the tool, the flexible 'handle is'equipped with a finger piece 40 having-a transverse force-applying pin 42 therein which is adapted to engage the outer side of the flexible handle portion 29. The *finger piece is kept in place on the flexible handle portion '29 -by a-pair of retainer pins 44 mounted on the handle portion 29. The pins 44 are spaced apart and'straddle the force-applying 'pin 42. Engagement 'of the pins 4'4 withthe force-applying pin 42 serves 'to' prevent longitudinal movement of the finger piece 40"with respect 'to the flexible handle portion 29, thereby insuring that a force tending to "flex the handle is always applied thereto at the same place.

Thestripping force to be measured is that required to effect initial movement of the convolutions of-the wire W with respect to the terminal T. As soon as movement of the wire 'with respect to-thc terminal 'begins, substantially less force is required to continue this relative 'movement, and there is no'interest in the latter force. it is desirable, therefore, that means be provided to indicate the maximum deflection of the handle portion 29, which occurs just at the instant that relative movement'between the wire and the terminal is about to begin. Thus, the finger 34, on which the scale 32 is formed, is provided with a rider '46 which frictionally engages the finger'and is adapted to 'be moved along the same, traversing the scale 32, by the outer end of" the flexible handle portion 29. The frictional engagement 'of the rider 46 with the finger 34 serves to retain it in place with respect to the scale 32 after movementthereof by the outer 'end of the flexible handle portion '29. In order to move the rider 46 along the arm 54 and *sca'leSZ, and to prevent lateral displacement of the flexible handle portion 29, the outer end of the latter is provided with an aperture 48 through which passes the finger 34. The aperture 48 is of course dimensioned with respect to the finger 34 was not to bind thereon, yet theaperture is of sufliciently small size to engage the rider '46 for movement thereof along the scale 32.

The operation of the foregoing inspection tool will be apparent from the foregoing. However, it may be summarized briefly as follows: When it is desired to determine the force required to strip the convolutions of a wire wound about "a terminal, the -terminal is inserted in the slots 14 and 22 of the jaws Hand 20, with the thumb screw 16 being tightened to clamp the terminal in fixed relation to the jaw'12, and in position for engagement of the wire W by the outer surface of the jaw '20. Thereafter, the user of the tool grips the handles 26 and 27 and applies a squeezing force thereto. Such force is applied to the flexible handle portion '29 byway of the finger piece 41) and its force-applying pin 42. As a result the handle portion 29 is displaced toward the rigid handle 26 with the result that the outerc'nd portion ofthe "flexible handle 29 causes the rider 1'6 tobe moved inwardly along the scale 32. Suchflexureof the handle portion 29, with the consequent traversal of the scale 32, continues until the wire W begins to 'bem-ovedaxially of'the terminal T. Since further force to 'move the wire'W with respect to the T is substantially less than that required "to initiate such movement, the flexible handle portion 29 tends to'return to its normal position, and the rider 46 is left at the point of maximum displacement thereof with respect to the scale 32. This permits an accurate reading of the maximum displacement, and thus of the force re- 4 quired to produce the same, directly from the scale 32.

"In --view -of the foregoing it will be seen that an inspection tool for determining the effectiveness of solderless wire connections constructed in accordance with the teachings of the present invention effectively measures the stripping force required to separate the wire and the terminal defining the connection. It is compact and easily manipu'lable, and by virtue of its extreme simplicity permits of economical-manufacture.

We claim .as our invention:

1. A tool for inspecting a connection between a wire and a terminal comprising, in combination, a pair of jaws having alined slots therein for the reception of the terminal, means for clamping the terminal to one of said jaws, the other of said 'jaws being engageable with the wire, a rigid handle .mounting said 'one jaw, 21 second handle mounting said other jaw and having a flexible portion, a finger piece carried by said fiexible portion and 'engageable therewith for the application of force thereto, a scale fixed to said second handle and adapted to be traversed by said flexible handle portion to indicate the amount of flexure of said portion with respect to said rigid handlewhereb'y to measure the amount of force applied to 'strip the wire from the terminal.

2. A tool for inspecting aconnection between a wire and a terminal comprising, in combination, a pair of jaws having alined slots "therein for the reception of the terminal, means for clamping the terminal in the slot ofone of said jaws, the other of said jaws being engageablewiththe wire, a rigid handle mounting said one jaw, a second handle mounting said other ,jaw and having a flexible portion, a scale "fixed to said second handle and adapted to be traversed by said flexible handle portion to indicate the amount of flexure of said portion with respect'to said rigid handle whereby 'to measure the amount of force applied to strip the wire from the terminal.

3. A tool for inspecting a connection between a wire and a terminal comprising, in combination, a pair of jaws having alined slots therein for receiving the terminal, a thumb screw on 'one of said jaws for clamping the terminal in the 'slot'there'in, the other jaw being engageable with the wire and movable with respect to said one jaw to apply .a force for stripping the'wire from the terminal, a rigid handle mounting one of said jaws and a relatively flexible handle mounting the other of said jaws, a scale fixed with respect 'to said one jaw-handle, and means for cooperation with said scale and flexible handle to indicate the amount offlexure of said flexible handle with respect to the other rigid handle upon operation of the tool to strip 'the wire from the terminal.

4. A tool for inspecting a connection between a wire and a terminal comprising, in combination, a pair of jaws adapted to receive the terminal inwardly of the Wire applied thereto, means on one of said jaws for supporting the same in fixed relation to the terminal, the other of said jaws being relatively movable with respect to said one jaw and adapted to engage the wire, said jaws upon relative movement thereof being adapted to apply a force axially of the terminal to strip the wire therefrom, and means for measuring said force including a rigid element fixed with respect to one of said jaws and a flexible element fixed with respect to the same jaw and movable with respect thereto and to said rigid element according to the amount -of force applied, one of said elements having a force indicating scale thereon adapted to be traversed by the other of said elements upon the application of said force.

5. A tool for inspecting a connection between a wire and a terminal wherein the connection is effected by intimately winding the Wire about the terminal, said tool comprising, in combination, a pair of jaws having alined slots therein for the reception of the terminal, means for clamping one of the jaws to the terminal, the other of said jaws ibeing engageable with the wire, a rigid handle mounting one of said jaws, a second handle mounting the other of said jaws, said second handle having a flexible portion, a finger piece carried by said flexible portion and having an element rigid therewith engageable with said flexible portion at a point intermediate its ends for the application of force to said flexible portion at said point, said jaws upon relative movement thereof being adapted to apply a force axially of the terminal to strip the Wire therefrom, a scale fixed to said second handle and adapted to be traversed by said flexible handle portion to indicate the amount of flexure of said portion whereby to measure the amount of force applied to strip the wire from the terminal.

References Cited in the file of this patent UNITED STATES PATENTS Smitak Feb. 22, 1927 Phillips Oct. 8, 1940 Wood Mar. 16, 1943 Koepnick et a1. Aug. 27, 1946 Milburn Jan. 17, 1950 Steadman Aug. 14, 1951 

